A common part of installing electronic equipment is the fastening of cable, such as the cable used in the telecommunications industry, to a surface such as a wall, a floor, a baseboard or other similar surfaces. The recent expansion of the telecommunication industry has caused an increase in the amount of sensitive cable being fastened to surfaces and has made more acute the need for a tool that conveniently, effectively and safely attaches such cable to surfaces and has made more acute the need for a tool that conveniently, efficiently and safely attaches such cable to a surface in a quick and efficient manner without damaging the cable.
Previous methods of fastening cable to a surface have made use of individual, manually applied clips or conventional staple guns. The use of manually applied clips to attach cable to a surface has proved to be time consuming and labor intensive, making this method economically unattractive. Attachment of cable by using a conventional staple gun is faster and more economical than use of clips, but it has been found that stapling may have a harmful effect on the cable, impairing its electrical characteristics and possibly creating safety concerns.
A conventional staple gun ejects a metal staple and often a point of the staple may lacerate the protective insulation as it passes next to the cable, or the force that must be utilized in this process may cause the cross member of the staple to crimp or cut through the insulating layer of the cable that houses the conducting wires. Thus the metal staple may cut the insulating layer thereby exposing the conducting wire and allowing moisture ingress, or it may crush the cable sufficiently to impair its ability to accurately transmit signals or it may actually sever one of the conducting wires. Furthermore, the amount of force imparted to the cable by the staple depends on the size of the cable against which it is coming into contact and the resistance offered by the surface into which the staple legs must penetrate. Therefore, a stapler with an ejection force appropriate to accommodate one cable size or one density of surface material may need adjustment before it can be safely used in another cable environment. The most common method presently used in the installation of sensitive cable is by the use of individual, manually applied clips. The need exists to make the installation of cable faster and easier while substantially eliminating crushing or severing of the cable insulation or the conducting wires.
One solution to the problem is disclosed in a copending application that discloses apparatus that includes a dual magazine staple gun in which one magazine contains protective encasements for surrounding the cable to prevent problems associated with the scraping or the crushing of the cable by a staple. A conventional staple gun having a magazine with staples is modified by providing a second housing assembly adjacent the bottom surface of the conventional stapler and substantially parallel thereto. The second housing assembly comprises a base member having a longitudinal cutout in the bottom surface and having side walls defining a chamber. A number of encasements are disposed in the chamber. The encasements have a slot on their lower surfaces which, in conjunction with the surface onto which the cable is being fastened, forms a channel for holding the cable when the clip is affixed to the surface. The clip has a foot member disposed on each side of the slot with a hole penetrating each foot member. A plurality of encasements are detachably fixed to each other in parallel fashion and disposed in the housing assembly chamber so that the feet of the encasements contact the floor of the chamber. A biasing member such as a spring has one of its ends positioned against a cover for the housing assembly and is attached at its other end to an encasement moving mechanism. The biasing member urges the encasement moving mechanism and thus the encasements forward in the housing assembly so that an encasement underlies the forwardmost of the staples in the staple gun.
In operation the slot in the base member of the housing assembly is positioned over the cable. The staple gun trigger lever is activated so as to move the forwardmost staple in the staple gun downward so that the staple legs pass through the holes in the feet of the underlying encasement the force of the ejected staple carries the encasement downward out of the staple gun so that the feet of the encasement contact the surface. The staple legs penetrate through the holes in the feet of the encasement into the surface to affix the encasement in an upright position. In this position, the slot in the underside of the encasement, in combination with the surface, defines a channel in which the cable lies. As a result, the encasement legs and cross member keep the staple spaced from the cable so that the cable is not contacted by the staple. In this manner of operation, substantially all of the momentum of the staple ejected from the staple gun is absorbed by the encasement and surface, rather than allowing the force of this momentum to be transmitted to the cable.